During the twentieth century, the real income of blue-collar workers in western societies overall, although it has in the past 20 years

Asmartphone manufacturing company uses social media to achieve different business objectives. match each social media activity of the company to the objective it the company achieve.

Reliability and validity reliability and validity are two important considerations that must be made with any type of data collection. reliability refers to the ability to consistently produce a given result. in the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. to illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. if the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. while the scale is highly reliable in producing consistent results (e.g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. this is where validity comes into play. validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. while any valid measure is by necessity reliable, the reverse is not necessarily true. researchers strive to use instruments that are both highly reliable and valid.

Suppose that electricity producers create a negative externality equal to $5 per unit. further suppose that the government imposes a $5 per-unit tax on the producers. what is the relationship between the after-tax equilibrium quantity and the socially optimal quantity of electricity to be produced?